deweloperuch-mcp

Ask an AI assistant about new-build apartments in Poland: asking prices with their history, real transaction prices and official statistics.

An unofficial MCP server and command-line tool over the public data of deweloperuch.pl: developers' asking prices (with price history), transaction prices from the Real Estate Price Register (RCN) and statistics of GUS and NBP. Thirteen read-only tools, usable from an MCP client such as Claude Desktop or Claude Code, or from the deweloperuch CLI.

Disclaimer. This is an independent project. It is not affiliated with, endorsed by or sponsored by deweloperuch.pl, GUS, NBP or the Register's publishers.

• It is read-only: it never creates or changes anything on the service.
• It is a polite client: at most 1 request per second, one at a time, shared by all processes on your machine; responses are cached; after a 401, 403, 429 or a captcha/WAF challenge it stops sending requests until you clear the lock yourself.
• Please respect the service. It is run by other people; ask narrow questions and do not build loops or bulk downloads on top of this tool.
• Data accuracy is not guaranteed. Prices are asking or registered prices, not valuations or advice.
• You are responsible for how you use the tool and the data, including the terms of the service.

What you can ask

• Buying a flat: "Find flats of 40–55 m² in Kraków's Podgórze up to 800 000 PLN, cheapest per m² first." (The service has no filter by number of rooms; filter by area instead.)
• Judging an offer's price: "Is this offer a good deal? Show its price history, the lowest price of the last 30 and 90 days, and whether the reduction looks suspicious."
• Checking a developer: "What does this developer build, and how many offers are active in which cities?"
• Market and transaction prices: "How do asking prices in Gdańsk compare with registered transaction prices over the last quarters?"
• Valuation: "Roughly what is a 55 m² flat at this address worth, based on nearby transactions?"
• Comparing cities: "Rank cities by transaction price per m², and show wages and unemployment next to them."

Install

Pick the option that fits you. Supported systems: macOS and Linux. Windows is not supported (the shared request limiter uses fcntl file locks).

1. Claude Desktop, one click

1. Download deweloperuch-mcp-<version>.mcpb from the latest release.
2. Double-click it, or drag it into Claude Desktop → Settings → Extensions → Install.

The first start installs Python and the dependencies with uv and takes about a minute. The extension has no command-line tool; if the server is ever stopped (STOP), see lifting a STOP without a checkout.

2. With uv, from PyPI

Requires uv. Nothing to clone. (pip install deweloperuch-mcp works too.)

Claude Desktop (claude_desktop_config.json; any MCP client that starts a stdio server works the same way). If Claude Desktop reports spawn uvx ENOENT, put the full path from which uvx in command:

{
  "mcpServers": {
    "deweloperuch": {
      "command": "uvx",
      "args": ["deweloperuch-mcp"]
    }
  }
}

Claude Code:

claude mcp add deweloperuch -- uvx deweloperuch-mcp

CLI:

uvx --from deweloperuch-mcp deweloperuch --help

3. With uv, straight from GitHub

The same as option 2 with --from git+https://github.com/MBratkowski/deweloperuch-mcp@v0.1.1 (@v0.1.1 pins the release; drop it to follow main):

claude mcp add deweloperuch -- uvx --from git+https://github.com/MBratkowski/deweloperuch-mcp@v0.1.1 deweloperuch-mcp
uvx --from git+https://github.com/MBratkowski/deweloperuch-mcp@v0.1.1 deweloperuch --help

In claude_desktop_config.json use "args": ["--from", "git+https://github.com/MBratkowski/deweloperuch-mcp@v0.1.1", "deweloperuch-mcp"].

4. From source (developers)

Requirements: Python 3.11 or newer and uv.

git clone https://github.com/MBratkowski/deweloperuch-mcp.git
cd deweloperuch-mcp
uv sync
uv run deweloperuch --help                  # sends no requests
uv run deweloperuch locations search krak   # first real request

As the client command use uv run --directory /path/to/deweloperuch-mcp deweloperuch-mcp (Claude Code: claude mcp add deweloperuch -- uv run --directory /path/to/deweloperuch-mcp deweloperuch-mcp). The server speaks stdio and logs to stderr. More: docs/mcp/README.md.

Tools

Overview, argument rules, errors and result sizes: docs/mcp/README.md.

Every tool rejects arguments that are not in its schema with an error that lists the allowed names. Tool descriptions, error messages and CLI output are in Polish, because the service and its users are Polish.

Prompts

Four ready-made prompts appear in Claude Desktop as commands. They send no requests themselves; they guide the model through the tools above. Arguments and details: docs/mcp/prompts.md.

CLI commands

Overview, output format and exit codes: docs/cli/README.md.

How it works

deweloperuch.pl  →  api  →  models  →  usecases  →  consumers (CLI, MCP server)

The layers are wired in bootstrap.py, and import-linter enforces the direction of imports. Design decisions and their reasons: docs/decisions.md. The service's data, endpoints and limits: docs/discovery/README.md. Configuration, the limiter and the STOP lock: docs/configuration.md.

Development

uv sync
make fast     # ruff, ruff format --check, mypy, import-linter (a few seconds)
make check    # fast + the offline tests + dead-code check + complexity and duplication reports

Every make target is offline; the tests never open a network socket and run against real responses stored in docs/discovery/samples/ and tests/fixtures/.

After an intended output change, refresh the golden outputs with DEWELOPERUCH_UPDATE_GOLDEN=1 uv run pytest tests/characterization and review the diff (tests/golden/README.md).

Live end-to-end tests are off by default. They check the installed server, the CLI and the helper scripts against the real service, so they send real requests. Run them sparingly, only when a change needs it:

DEWELOPERUCH_LIVE=1 uv run pytest -m live tests/e2e -rs --maxfail=3

Both the variable and -m live are required. Scenarios and request budget: tests/e2e/README.md. Contributing guide and release procedure: CONTRIBUTING.md.

Documentation

Data sources and licences

• deweloperuch.pl: the source of all offer, investment, developer and statistics data. Its terms apply to your use of the data.
• RCN (Real Estate Price Register) transaction data, reached through the service. The service's authors publish raw RCN data as CC0 in their public repository.
• GUS (Central Statistical Office) and NBP (National Bank of Poland) statistics, reached through the service. Name them as the source when you republish figures.

The code is licensed under the MIT licence. The licence covers code only; the samples and fixtures used for testing contain data from the sources above and are described in NOTICE.

Contributing

Issues and pull requests are welcome; please read CONTRIBUTING.md first, especially the polite-client rules. Security reports: SECURITY.md.